Facial flushing, edema of lips, and dyspnea after drinking white or red wine but could eat fresh grapes without a problem. However, exercise-induced anaphylaxis after eating white grapes and then exercise. After exercise, urticaria, facial/pharyngeal edema, abdominal pain, and dyspnea appeared and rapidly worsened (Senna et al 2001 [706])

The skin test was positive with a 10 mm wheal and 14 mm erythema above the saline control (Vaswani et al. 1999) [551].

Prick-to-prick. The test was defined as positive with a wheal diameter of at least 3 mm (Bircher et al. 1999) [869].

Prick-plus-prick technique. A positive skin reaction was defined as the presence of a wheal larger than that elicited with the histamine phosphate control as read after 20 minutes (Pastorello et al. 2003) [707]

Prick test and prick-by-prick test. The tests were positive when a wheal diameter of at least 3 mm was observed (Caiaffa et al. 2003) [708].

Immunoblotting

Immunoblotting separation:

SDS-PAGE was performed on a 10% polyacrylmide gel (Senna et al. 2001) [706]

The extracts were separated in a discontinuous buffer system in an SDS-polyacrylamide gradient gel with a 6% stacking gel and a 7.5% to 20% separation gradient gel under reducing conditions (Pastorello et al. 2003) [707]

The separated proteins were electroblotted onto a nitrocellulose membrane. The nitrocellulose was incubated with each patient's serum diluted 1:4 in blocking solution. The bound specific antibodies were detected by means of incubation with iodine 125–labeled anti-human IgE antiserum and exposure on x-ray film (Pastorello et al. 2003) [707]

Immunoblotting results:

A 31 kDa protein was recognised by IgE from the sera of the 3 patients (Anton et al. 1997) [961].

A 94 kDa protein was recognised by IgE in sera from a single patient (Rodriguez et al. 2001) [705].

A 30 kDa grape protein was recognised by IgE in sera from a single patient (Senna et al. 2001) [706]

Other biochemical information:The results of both MALDI and ESI MS/MS analysis indicate that this component might be an isoform of the grape class IV endochitinase VVCHI4B that is slightly different from that described by Robinson et al. 1997

The thaumatin-like proteins (TLPs) contain 8 disulfide bridges and so it might be expected to be thermostable. The TPLs are generally resistant to proteases and pH-induced denaturation (Breiteneder, H. 2004) [1001]

Allergen properties & biological function:Due to high sequence identitiy of grape thaumatin-like protein and Pru av 2 (42% identity and 78 % similarity) it is though to display similar functions as other thaumatin-like proteins. These proteins have been included in the pathogenesis-related proteins classification as PR5 and are thought to be produced in response to pathogen infection or to osmotic stress.

Due to the high sequence identity of grape LTP to peach LTP it is though to display similar functions as other plant nonspecific lipid-transfer proteins. They are thought to be involved in transport of fatty acids both intracellular and extracellularly and of cutin monomers to the cuticular layer of leaves and fruits. There is an expandable cavity between the four alpha-helices which can bind one or two lipids. nsLTPs have also been reported to act as plant defense proteins against bacterial and fungal infections and form the PR14 family of pathogenesis related proteins. It is possible that a lipid-like post-translational modification is involved (Lindorff-Larsen et al. 2001 [903]).